Question about NoAccel vs Trbvh

I recently met an issue when playing with acceleration structures.Hope someone could give me a hand.
In my scene structure it’s just one top_group(Trbvh)->some xfroms-> GeometryGroup(Trbvh)->Geometry Instance->geometry
It works fine.
Now i assign a invisible material to one geometry instance(a material with anyhit just rtIgnoreIntersection())
it still works fine and that object is invisible.

Here comes the issue.
When I apply a scale to the object’s xform and scale it down to 0.99 on x,y,z. That object change to black color instead of invisible.
But if i change the top_group structure to NoAccel. The scaled down object looks invisible again which is what I want.
So far I only found scale down will affect the invisible object. Scale up seems ok. rotation and translation is ok.

my question:
1:is this a bug for trbvh structure? (i also tried Bvh the same issue.)
2:Since NoAccel works fine but it affect performance what’s the better options here?
thanks you

That’s potentially a known issue inside OptiX.
Similar case here: [url][/url]

You could try if the OptiX 5.1.0 experimental execution strategy solves it, but that is really very limited in its implemented features in that version.

thanks Detlef for answering my question.
When I try your experimental strategy before the context creation the app crashs.
this is the code i enable:

int expexeconoff = 1;
if (rtGlobalSetAttribute(RT_GLOBAL_ATTRIBUTE_EXPERIMENTAL_EXECUTION_STRATEGY, sizeof(expexeconoff), &expexeconoff) != RT_SUCCESS) {

i’m using optix 5.1 on a titanV with latest driver windows 10.
Will the next release fix this issue?

If it’s the same error as I think, then it’s not happening in a newer internal version of that code path in OptiX anymore and the next major release should pick it up. I cannot comment on release dates though.